Why can powder bulk density change during production?
Powder bulk density can change as product is conveyed, aerated, vibrated, compacted, stored or replenished, so the same apparent volume may not always represent the same mass. Record how the production powder reaches the filler, not only how a hand sample was prepared. Compare start-up, steady running and low-hopper conditions and decide whether the process controls volume, mass or a separate check.
What causes powder to bridge in a hopper?
Powder bridges when particles form a stable arch or cohesive mass above the outlet, preventing consistent flow even though material remains in the hopper. Moisture, fine particles, compaction, hopper angle, outlet size and time at rest can contribute. A trial should include realistic pauses and replenishment. The remedy must be selected carefully because uncontrolled vibration or agitation can change density.
When can agitation help or worsen powder flow?
Agitation can help when it breaks a predictable bridge or presents powder consistently to the dosing element, but it can worsen flow by compacting, aerating, segregating or damaging the product. Define speed, geometry and run condition through trials. Do not assume more agitation is better. Observe dose results and the physical state of the powder at different hopper levels.
Can one powder recipe be reused after a new batch arrives?
A powder recipe should be reused only when the new batch remains inside the approved material envelope for density, moisture, flow, particle distribution and handling history, or after a defined verification confirms the result. A product name or supplier certificate may not capture every process-relevant difference. Use change control and a routine check at start-up. For mass-based decisions, compare the gross and net weight sequences.